Electric clock



Dec. 5, 1950 'r. K. RIGGEN ELECTRIC cnocx Filed Nov. '26, 1945 INVENTOR.

Patented Dec. 5, 1950 ELECTRIC CLOCK Theodore K. Riggen, Elmira, N. Y., assignor to Bendix Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application November 26, 1945, Serial No. 630,901

Claims.

The present invention relates to electric clocks and more particularly to clocks which are intended to operate on low voltage direct current as in automotive installations.

It is an object of the present invention to provide a direct current electric clock which is accurate and reliable in use, insensitive to temperature changes and simple and economical in construction.

It is another object to provide such a device which is efficient in operation so as to entail a negligible drain on the battery.

It is another object to provide such a device which utilizes magnetic fields for the storage of energy to operate the clock, thus eliminating the springs which are used for that purpose in conventional types of clocks.

It is another object to provide such a device in which magnetic flux is substituted for springs in the actuation of the pawl mechanism of the drive. X

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a perspective view, partly diagrammatic in form, of a clock mechanism constituting a preferred form of the invention; and

Fig. 2 is a top view of the actuating mechanism for the clock showing the parts at the end of the power stroke thereof.

In Fig. 1 of the drawing, there is illustrated a permanent magnet I which is preferably of U shape so as to bring its poles 2, 3 into substantially co-planar relation.

An actuating member in the form of an electromagnet, indicated generally by numeral 4, is rotatably mounted adjacent the magnet I so that one end of the core 5 thereof may swing toward and away from the pole 2 of the magnet l. The electromagnet comprises a coil 6 which is connected at one end by a lead I to a battery 8 which is grounded at 9, and the other end of the coil is connected to an insulated contact II mounted on the core 5 of the electromagnet opposite the pole 2 of the permanent magnet I.

Means for controlling the energization of the electromagnet is provided comprising an armature I 2 pivoted at I3 on the core 5 of the electromagnet .and grounded as indicated at I4, which armature carries a contact I5 adapted to cooperate with the contact I I on the electromagnet.

The armature I2 is prevented from coming into direct contact with the pole 2 of the permanent magnet I by means of a spacer I6 of non-magnetic material which may be aflixed to the armature or the permanent magnet. Means for limiting the movement of the armature l2 away from the permanent magnet is provided in the form of a bracket I'I fixed to the permanent magnet and having a shoulder I8 adapted to engage the end of the armature I2.

The direction of current flow through the coil 6 of the electromagnet 4 is such that when the circuit therethrough is closed the electromagnet is magnetized with the same polarity as the permanent magnet I, whereby the electromagnet will be vigorously repulsed thereby and will rotate about its pivot I9 in a counterclockwise direction as viewed in Fig. 2. This motion may be limited if desired by a stop member 2 I.

The armature I2, being directly attached to the core 5 at its pivoted end and being closely adjacent thereto at its free end, is more strongly. attracted by the electromagnet 6 than by the permanent magnet I from which it is spaced by the non-magnetic member I6. Contacts I I, I5 are preferably made of magnetic material such as a sintered mixture of powdered iron and copper, whereby this preponderating effect of the electromagnet on the armature I2 may be augmented. The result is that, when the electromagnet is energized, the armature I2 moves with the electromagnet away from the permanent magnet I, thus keeping the contacts II, I5 closed until the motion of the armature I2 is arrested by the bracket IT. The contacts II, I5 are thereby opened and the electromagnet consequently deenergized.

A ratchet mechanism for utilizing the movement of the core 5 of the electromagnet toward the permanent magnet I to operate a clock mechanism is provided comprising a ratchet wheel 22 mounted co-axially with the core 5 on the pivot I9, and a pawl 23 pivoted on the core 5 in position to engage the teeth'of the ratchet wheel. Pawl 23 may be urged into engagement with the ratchet wheel 22 by a spring in the conventional manner, but it is preferred to eliminate such a spring by utilizing a magnetic member 20 fixed on the pawl 23 and an armature 20 of ferrous material on the core 5 in such position that the mutual attraction between the magnetic member and armature causes the pawl to be held in engagement with the ratchet wheel.

The ratchet wheel 22 is fixedly mounted on the sleeve I9 which constitutes the journal for the core 5 of the electromagnet and a gear wheel 24 is also fixed on said sleeve to rotate therewith. Gear 24 drives a pinion 25 fixed on a shaft 25 3 mounted in the bearing 21, which shaft carries a second pinion 28 and a gear wheel 29. Gear 29 meshes with a pinion 3| fixed on a shaft 32 which extends axially up through the gearing and carries a sweep second hand not illustrated which is arranged to rotate at one revolution per minute. The pinion 28 drives a gear 33 which is fixed on a sleeve 34 extending upwardly and carrying at its upper end a minute hand, not illustrated, arranged to make one revolution per hour. Gear 33 also carries a pinion 35 meshing with a gear 36 fixed on a shaft 3! carrying a pinion 38 which meshes with a gear 39 fixed on a sleeve 4|, the upper end of which carries an hour hand which makes one revolution every 12 or 24 hours .ac-

cording to the type of clock desired.

The pinion 3| has fixed thereto a gear 42 which meshes with a pinion 43 mounted on-ashaft -44 carrying a gear 45 which in turn meshes with :a pinion 46. Pinion 4G is attached to a disc 41 of electrically conductive material such as aluminum, which disc is accordingly rotated several times as fast as the shaft 32 carrying the sweep second hand.

Means for governing the speed of rotation of the disc 41 and consequently regulating the clock mechanism is provided in the form of a permanent magnet 48, the poles 49 and of which are located closely adjacent the upper and lower surfaces of the disc, whereby a concentrated magnetic flux traverses the disc. The rotation of the disc is consequently impeded by a force which varies directly with its speed, such force being the resultant of the interactionof the eddy currents induced in the disc by and with the flux of the permanent magnet in the well-known manner.

Means for adjusting the speed of the disc is provided by moving the magnet 48 radially with respect thereto by suitable adjusting mechanism indicated generally at 52.

It will be understood that in the illustration the framework and the bearings of the clock work are omitted for the sake of clarity and in view of the fact that they constitute no part of the present invention.

In operation, starting with the parts in the positions illustrated in Fig. 1, the attraction of the permanent magnet l for the core 5 of the electromagnet which is at this time deenergized causes said core to move in a clockwise direction, which motion is transmitted through the pawl 23 to the ratchet wheel 22 whereby the clockwork and disc 41 are rotated, the speed of rotation being governed by the magnet 48. When the core 5 of the electromagnet approaches the permanent magnet l sufficiently to bring the contact ll into engagement with the contact I5, the circuit through the coil 6 of the electromagnet is completed, whereby the electromagnet is energized with like polarity to the permanent magnet l and is conseqently vigorously repulsed therefrom. At the time, the armature i2, .being more strongly attracted by the electromagnet than by the permanent magnet I, accompanies the electromagnet in its counterclockwise movement until the end of the armature l2 engages the shoulder iii of the bracket IT. The movement of the armature is thus arrested, whereby the contact I l moves away from contact [5 breakingthe circuit through the coil 6 which is thus deenergized. The armature I2 is then free to return to its original position against the spacer l6 under the attraction of the permanent magnet I. The core 5 is also attracted by the magnet I and, since it is connected to the clockwork and the disc 41 through the pawl 23, its movement toward the magnet I is governed by the speed of rotation of the disc 41, and the energy developed by this movement is used to operate the clock.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the form and arrangements of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an electric clock, a permanent magnet, an electromagnet including a core of magnetic material mounted for movement toward and away from the permanent magnet, means for intermittently causing repulsion of the electromagnet from the permanent magnet, and clock mechanism driven by movement of the electromagnet toward the permanent magnet caused by the attraction of said core by the permanent magnet when the electromagnet is deenergized, said means for causing repulsion of the electromagnet including a source of electrical energy, a circuit connecting the electromagnet to said source, an armature movably mounted on the electromagnet between the electromagnet and the permanent magnet, and a pair or contacts in said circuit mounted on the electromagnet and the armature respectively.

2. In an electric clock, a permanent magnet, an electromagnet including a. core of magnetic material pivotally mounted adjacent the poles of the permanent magnet, a clock work, means for driving the clockwork by the rotary motion of the electromagnet toward the permanent magnet caused by the attraction of said core by the permanent magnet when the electromagnet is deenergized, and means for energizingthe electromagnet with like polarity to the permanent magnet including a source of electricalenergy,a'circuit connecting the electromagnet to said source, an armature of magnetic material pivotally mounted on the electromagnet adjacent the permanent magnet, a contact on the electromagnet, a cooperating contact on the armature said contacts being arranged to open and close said circuit, non-magnetic spacing means preventing the armature from engaging the permanent magnet, and means for limiting the movement of the armature away from the permanent magnet.

3. An electric clock as set forth in claim 2 in which said contacts are of magnetic material whereby energization of the electromagnet .holds the contacts closed.

4. In an electric clock a permanent magnet, an electromagnet having a core of magnetic material mounted for movement toward and away from the permanent magnet, means for intermittently causing repulsion of the electromagnet from the permanent magnet, and clock mechanism driven by movement of the electromagnet toward the permanent magnet caused by the attraction of said core by the permanent magnet when the electromagnet is deenergized; in which said means for causing repulsion of the electromagnet includes a source of electrical energy, a circuit connecting the electromagnet to said source, an armature movably mounted on the tacts, and attraction by the electromagnet tends to close the contacts; and means for limiting the separation of the armature from the permanent magnet.

5. Driving mechanism for an electric clock including a permanent magnet, an electro-magnet having a core of magnetic material mounted for rotary movement toward and away from the permanent magnet, means for energizing the electromagnet with the same polarity as the permanent magnet including a source of electrical energy, a circuit connecting the electromagnet to said source, a pair of contacts in said circuit,

means for closing the contacts when said core' reaches the end of its movement toward the permanent magnet caused by the attraction of the permanent magnet for said core when the electromagnet is deenergized, and means for opening the contacts at the end of its movement away from the permanent magnet; said means for opening and closing the contacts including an armature pivotally mounted on the core of the electromagnet for controlling the contacts, said armature being attracted by the permanent magnet and thereby holding the contacts open while the electromagnet is deenergized, and being attracted to the electromagnet to hold the contacts closed when the electromagnet is energized; said contacts being so constituted as to assist in the transmision of flux from the electromagnet to the armature.

THEODORE K. RIGGEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

